fix(postprocessing): add output and fix --restart flag for resume command

[paul43210]

Summary

Fixes #11692 — ocis postprocessing resume produces no output and the --restart flag is broken.

• Flag mismatch: c.Bool("retrigger") referenced a non-existent flag — corrected to c.Bool("restart") so the --restart / -r flag actually triggers RestartPostprocessing events
• No output: The command now connects to the postprocessing store, queries matching uploads, and displays them in a table before publishing events
• New --json flag: Outputs matched uploads as a JSON array for scripting
• Empty store handling: Gracefully handles empty NATS KV buckets instead of returning an error

Example output

$ ocis postprocessing resume --step finished
┌──────────────────────────────────────┬──────────────┬──────┬──────────┬──────────┬──────┐
│              UPLOAD ID               │   FILENAME   │ SIZE │   STEP   │ FINISHED │ USER │
├──────────────────────────────────────┼──────────────┼──────┼──────────┼──────────┼──────┤
│ a5b81897-0471-4ca0-9965-259263363f35 │ New file.txt │ 4    │ finished │ false    │ paul │
└──────────────────────────────────────┴──────────────┴──────┴──────────┴──────────┴──────┘

Resumed 1 upload(s) at step "finished"

Test plan

• ocis postprocessing resume --step finished — shows table of uploads and count
• ocis postprocessing resume --upload-id <id> — shows single upload
• ocis postprocessing resume --restart --upload-id <id> — uses RestartPostprocessing event
• ocis postprocessing resume --json --step finished — outputs valid JSON array
• ocis postprocessing resume --step finished on empty store — prints "No uploads found" gracefully

🤖 Generated with Claude Code

[mmattel]

@paul43210 pls add a small update of the postprocessing readme

[jvillafanez]

I've commented on the linked ticket.
I'd keep the PR on hold for now. For me, this is a non-issue, so showing a "success" message is a nice-to-have. If this is the case, this PR is too much for a "we did what you asked" message.

If we need to show what is the postprocessing state, it should have its own command.

From my point of view, the PR should just fix the issue with the invalid / missing flag. If you want to be nice, you can show a simple output on success. Changes should be around 5 lines of code. The rest seems a different feature.

[paul43210]

Thanks for the feedback @jvillafanez — you're right, the store introspection was out of scope for this fix.

I've slimmed it down to just the essentials:

1. Fixed c.Bool("retrigger") → c.Bool("restart") so the --restart / -r flag actually works
2. Added a simple success message after publishing the event

The diff is now ~5 lines of code across a single file + changelog. The store query / table output can be a separate feature if needed down the road.

[jvillafanez]

I've restarted the CI because there were some unrelated test failures. Code looks fine.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[kobergj]

@paul43210 merged. Thanks for the find and the fix!